People v. Bonilla, 120 N.E.3d 930

Officers received a tip that Derrick Bonilla was selling drugs from his third-floor apartment in a three-story, 4-units-per-floor building; exterior building doors were unlocked.
A canine officer walked a trained narcotics dog through common hallways; the dog alerted at the threshold of unit 304 (Bonilla’s door).
Police obtained a warrant based on the dog alert, searched the apartment, and found cannabis; Bonilla was charged with possession with intent to deliver.
Bonilla moved to suppress; the trial court granted the motion, reasoning the hallway/threshold should be treated like a single‑family home threshold.
The appellate court affirmed; the State appealed to the Illinois Supreme Court, which also affirmed suppression and rejected the State’s good‑faith exception argument.

Issue	Plaintiff's Argument (People)	Defendant's Argument (Bonilla)	Held
Whether a warrantless K‑9 sniff at an apartment‑door threshold in an unlocked multiunit building is a Fourth Amendment search	Common hallway not curtilage; unlocked common area is public, so sniff was not a search	Threshold/landing is part of home curtilage; K‑9 sniff at door is a physical intrusion and thus a search	The hallway/threshold is curtilage; K‑9 sniff at threshold was a Fourth Amendment search and violated defendant’s rights
Whether the good‑faith exception to the exclusionary rule saves the evidence	Officers reasonably relied on Supreme Court and existing appellate authority holding K‑9 sniffs in public areas are not searches	Jardines/Burns control; no objectively reasonable precedent authorized a dog sniff of the home’s threshold	Good‑faith exception does not apply; officers lacked objectively reasonable binding precedent authorizing the conduct

Florida v. Jardines, 569 U.S. 1 (2013) (warrantless use of a drug‑detection dog on a home’s front porch is a Fourth Amendment search)
Collins v. Virginia, 138 S. Ct. 1663 (2018) (curtilage includes areas adjacent to home; physical intrusion onto curtilage to gather evidence is a search)
People v. Burns, 2016 IL 118973 (Ill. 2016) (apartment‑building hallway outside an apartment door is curtilage; K‑9 sniff of threshold required a warrant)
People v. Smith, 152 Ill. 2d 229 (1992) (diminished expectation of privacy in common areas of apartment buildings for overheard conversations; distinguished here)
Illinois v. Caballes, 543 U.S. 405 (2005) (K‑9 sniff during lawful traffic stop generally not a Fourth Amendment search because it reveals only presence of contraband)
United States v. Place, 462 U.S. 696 (1983) (canine sniff of luggage at airport is not a search because it discloses only presence of contraband)